Train control



Sept. 17, 1940. Q g, PARDEE 2,215,051 I TRAIN CONTROL Original FiledFeb. 9, 1951 2 Sheets-Sheet. 1

PT BR BR F IGJ. P4 Q 1 9 L 5p BR I HC 7 Ex I w I o H A EAD CAR I PU P4HEAD CAR Sept. 17, 1940. H. s. PARDEE TRAIN CONTROL 2 Sheets-Sheei 2Original Filed Feb. 9, 1931 FIGS.

Patented Sept. 17, 1940 PATENT OFFiCE 7 TRAIN CONTROL Harvey S. Pardee,Ravinia, 111.,

assignor, by

mesne assignments, to Hydromatic Corporation, Chicago, 111., acorporation of Illinois Divided and this application September 3, 1937,Serial No. 162,272

8 Claims.

This invention relates to control systems, and with regard to certainmore specific features, to train control systems.

The invention comprises an improvement upon the control apparatus shownin my Patent The invention is a division of the invention described inmy patent application, Serial No. 514,441, filed February 9, 1931, forTrain control,

eventuated into Patent No. 2,092,014, dated September '7, 1937.

Among the several objects of the invention may be noted the provision ofa control system for op- I crating the brakes, doors and related partsof conveyances such as rail cars, coaches, buses or the like in which anadaptationis made to trains of two or more vehicles.

Another object of the invention is to improvedly control from a singlepoint one or more func- '20 tions on several vehicles, there beingeffected a connection between the vehicles and certain automaticoperating means whereby difficulties caused by a. break in the train areminimized.

Another object of the invention is to effect optimum control of alimited number or any number of cars.

Another object is to provide a system adapted easily to coordinate brakecontrol features with door control and like features.

Other objects will be in part obvious and in part pointed outhereinafter.

It is to be understood that the cars or conveyances or vehicles to whichthe invention may be applied may be driven by electric or other motorsor means and are provided with the usual body constructions suiting themto their particular purposes.

The systems to be described herein refer to cars and trains of cars forstreet railway operation, electric and steam train operation and othertrains of trucks and the like.

The vehicles referred to are provided with brakes, preferably of thefriction type contacting with some rotating elements of the vehicles.

The invention accordingly comprises the elements and combinations ofelements, features of construction, and arrangements of parts which willbe exemplified in the structure hereinafter described, and the scope ofthe application of which will be indicated in the following claims.

In the accompanying drawings in which are i1- lustrated several ofvarious possible embodiments of the invention,

Fig. 1 is a diagram illustrating certain connections in applying theinvention to a train of a limited or low number of I cars with the headcar containing a control as well as brake energy generating and storageapparatus;

Fig. 2 is a diagram illustrating connections to be used in a train ofany number of cars; 5

Fig. 3 is a diagram showing the use of a fluid control line instead ofan electric control line;

Fig. 4 illustrates a method of coordinating dooroperationwith trainoperation;

Fig. 5 illustrates a form of door-control sys- 10 tem;

Fig. 6 is a view showing a certain form of brake mechanism; and,

Fig. '7 illustrates an electromagnetic brake valve.

Similar reference characters indicate corresponding parts throughout theseveral views of the drawings.

The drive for the vehicle herein described may comprise the spur or wormgear type, with brakes 20 operating in connection with a drive shaft orthe wheels. In Fig. 1 such a drive is diagrammatically illustrated ascomprising a motor M driving a worm W, the latter meshing with asuitable worm gear A on an axle of the vehicle. As above 25 indicated,the brakes may include shoes which are pressed directly against thewheels.

The braking system herein is represented as comprising a system of brakelines and cylinders BR which force friction brakes against the drivingparts of the vehicle. The brake cylinders BR receive fluid pressure inthe ordinary manner but, instead of being provided with pistons, theyare provided with internal, movable bellows I which are positivelyleak-proof. Each of the bellows I is connected on the outside with thebrakes, this being done by means of a suitable linkage 3. On the inside,each bellows I is exposed to fluid pressure. The movement is enough toset and release the brakes. -40

As shown in Fig. 1, the brakes may be set by spring 5 reacting againstthe bellows I through the linkage 3. Thus when pressure is admitted tothe bellows I, the brakes are released against spring pressure. Or theconventional method may be used, such as shown in Fig. '6 and certainother figures, wherein fluid pressure operates directly through knownlinkages to set the brakes.

It is to be understood that the construction shown in Fig. 6 may beapplied to the other figures, as designated hereinafter. It is to beunderstood that the linkages 3 are representative of any type that maybe desirable.

Bellows are also placed in series with the hose connections I-IC betweencars (Fig. 1). In this case there are cylinders I with internalseparating bellows 9 dividing cylinders I each into two chambers. Theconnections will be clarified hereinafter. It is to be understood thatthe bellows, wherever referred to herein, are representative of any andall types of substantially movable diaphragms or means adapted totransmit motion but to prevent passage of fluid.

As shown in Fig. 1 brake valve BP is a threeway, manually operable valveof the tapered plug or any other suitable type. It is used forconnecting the brake line BR alternately to a pressure tank PT (overpressure line PL) or a sump tank ST (over release line RL).Modifications of this valve are used in different applications, mcludingthose involving automatic operation; and the connections therefor willbe clear from the context.

An electromagnetic brake valve BV, in certain alternatives used on eachcar (Fig. 7), comprises an electromagnet E, the movable core 33 of whichis connected to the actuating arm 35 of a threeway valve l5 and to thecenter of a diaphragm DA subjected on the opposite side to the pressurein the line BR leading to the brake cylinders. A spring ll acts againstthe core 33 to move it in the direction of applying fluid pressure tothe brake linkages 3. As the current in the coil 3'! of the magnet E isincreased the core acts against the spring and tends to shut offpressure from the pressure line PL to the brake line BR and next toconnect the brake line BR tothe return line RL, thus relieving the brakelinkages of pressure.

The reaction of the diaphragm. DA is to oppose both actions and thus tobring about a condition of stable balance for each value of the controlcurrent. At zero current the spring overcomes the diaphragm pressureuntil full actuating pressure is admitted. At maximum current the corecompresses the spring and turns the valve to release the pressure on thebrake line (and under the diaphragm) so that finally the balance betweenspring and coil is reached with zero pressure on the diaphragm.

The tank PT comprises a pressure tank designed to withstand the airpressure used and to be air, oil and water tight, for example, the tankpressure may be 100 pounds per square inch.

The sump tank, indicated by letters ST, is under atmospheric pressureand preferably placed at the lowest part of the system to receive thedrainage from: the door engines (if there be such) and brake cylinders.The size of this tank is preferably such that when full it will holdsuch a quantity that, when substantially all of its contents are pumpedinto tank PT, the pressure in tank PT will be raised from minimum toslightly above a working maximum, providing tank PT is initially filledwith air at the minimum operating pressure.

Other details regarding these tanks and their connections may be foundin said Patent 1,784,310.

The hydraulic pump PU is preferably of the rotary positive type, andconnected directly to a moving axle or propeller shaft of the vehicle.

It thus starts and stops with the motion of the car or engine. It shouldbe arranged with a minimum amount of initial slip so that when the pumpstarts the pressure on the delivery side will build up quickly. Thispump needs to have but a small pumping capacity because the demands forliquid quantity are relatively small when non-expansive fluid is'usedinstead of an expansible gas. By-passes and other auxiliary pumpequipment are not here shown inasmuch as they have been disclosed insaid Patent 1,784,310, enough having been herein disclosed to make clearthe improvements.

Although it is possible to apply the present invention to a pneumaticsystem, it is preferable that a hydraulic system be used. The hydraulicfluid to be used in the present system comprises preferably a liquidrelatively non-expansive and non-compressible as compared with gasessuch as air. It should be selected with a viscosity reasonably constantat the various operating temperatures; it should not corrode metal andshould have a low enough vapor tension so as not to create anappreciable vapor pressure at the operating temperatures. It should notdeteriorate with time or use. It will be seen from the above that fluidssuch as are now known for hydraulic braking systems may be used, or oilor the like.

The operation of the pump PU, pressure tank PT and sump tank ST has beenmade clear'in Patent 1,784,310, but broadly speaking, the sump tank STcarries a charge of liquid (Fig. l). The pressure tanks PT carry acharge of air. The pump PU pumps liquid from the sump tank ST into thepressure tank PT to build up the pressure therein to a point where saidpressure is useful through the liquid as a compression link, to apply orrelease the brakes, depending upon whether the brakes are to be directlyset or spring set. Excessive pressures are avoided by suitable pumpby-passes and/or slip as stated in said patent.

The cars are each provided with a section of through pipe BR and thebrake fiuid is caused to move back and forth in the line as the controlvalve BP is moved between application and release positions, that is,between positions connecting train line or through pipe BR with thepressure tank PT and the sump tank ST.

In order to prevent loss of liquid in case of a break in the pipe lineBR, there is provided the diaphragm or expansion bellows EX in the lineat the rear of each car. The possible movement of this bellows isgreater than the displacement necessary to operate the brake linebellows I which are in connection with the train line BR, so that thebellows EX has no effect in ordinary operation but acts to stop the flowshould a break occur beyond the bellows.

Fig. 1 illustrates diagrammatically the connections, in which PUindicates the pump pumping liquid from the sump tanks ST into thepressure tanks PT partly filled with air under pressure. BP indicatesthe manually operable, three-way, brake valve connecting the line BRalternately to the pressure tank or to the sump tank. The bellows orpistons l of the brake cylinders operate to effect pressure on the brakeshoes through the usual rigging or otherwise; or, as forecast above, thebrake shoes may be applied by means of springs and the pistons of thebrake cylinders act to withdraw the spring pressure when the fluidpressure is applied to the brake cylinders and associated line BR.

Fig. 1 shows the spring pressed type of brake control wherein the brakesare operated by the spring 5 through the rigging 3, the pressure in thebrake cylinder arrangement BR reacting against the spring to release thebrakes. Or, the arrangement of Fig. 6 may be applied to Fig. l byconnecting the brake cylinder and line BR thereof to the line PL throughvalve BP when a brake setting is made.

Referring again to Fig. 1, the expansion bellows EX 9 is interiorlyconnected with the hose connections between the cars, that is, one ofeach of the two chambers of each bellows device EX is connected with thelines BR of successive cars. If a break occurs, such as in a hoseconnection, as shown at 1-10, the expansion bellows ahead is compressedand the brakes of the cars behind the break are automatically set if thebrake linkage of Fig. 1 is used. No liquid is lost from the tank PT.This system is primarily applicable to cars pulling one or a fewtrailers, that is, with a-relatively short train line PL, because of therequirement that the bellows EX have displacement greater than thatrequired to operate all of the brake cylinders positioned thereafter inthe train line. The cylinders BR may also represent cylinders foropening and closing doors controlled from the head car or for performingany other desirable operation. Two or more lines may be run, forinstance, one for operating brakes, and another for operating doors.

It is clear that, if the spring-pressed brake linkage of Fig. 1 be used,a break in the train line beyond the bellows EXresults in a pressurebeing taken off the bellows l with a resulting automatic setting by thesprings 5, as above described.

If a brake linkage is used wherein direct action is employed from thepressure fluid to the friction surfaces, instead of employing a springfor storing energy and later applying it, then a break in the train line(Fig. 1) beyond the first car does not result in automatic brake settingbut the operator in the first car can still set the brakes in the firstcar whenever he chooses. That is to say, a train line break does notresult in loss of braking fluid.

It will be understood that, when the spring brake linkage is used, thetank PT is put into communication with the brake line BR when it isdesired to force the brakes to release against spring pressure; and theline BR is placed in communication with the tank ST when it is desiredto set said brakes by means ofsaid springs. When the direct acting brakelinkage of Fig. 6 isapplied to the system'of Fig. 1, brake setting isaccomplished by placing the brake line BR into communication with thepressure tank PT by operation of valve BP.

In Fig. 2 is shown a second form of the invention. This second form ofthe invention has 'to do with a train of any number of cars wherein thecontrol and brake energy generating apparatus are in the head car buteach car contains energy storage means supplied from the head car,through a train pressure pipe line. On each car is a brake valveconnecting the brake cylinders of that car alternately to the pressuretank on that car or to a return line running the length of the train andconnecting intothe sump tank on the head car. The operating valves oneach car are controlled from the head car by electric lines. The controllines are arranged so that a break in them will set the brakes and theenergy storage apparatus on each car is not dangerously affected by abreak in the supply line. Should the train pull in two, both halves ofthe train are automatically stopped. Fig. 2 illustrates one form of thissystem showing equipment on the first two cars of a train. Similarletters refer to corresponding elements described in Fig. 1.

Referring to Fig. 2, PS indicates a pressure tank, one of which isinstalled on each car. The head car also carries a pressure tank PT. BVis an electromagnetically controlled brake valve on each car, BP is arheostatic hand-controlled lever in the head car, BY is the operatingsource of E. M. F. and BL is the fluid return line. All of the brakevalves BV operate simultaneously by control of the rheostat BP. Liquidpressure is thus admitted from the respective pressure tanks PS to therespective brake cylinders on the respective car, thus causing thebrakes to be set or released, depending upon whether springs are used toapply the brakes or direct fiuid pressure. The direct fluid pressuremethod is shown in the brake linkages of Fig. 2. When the fluid isreleased it fiows to the return line and to the sump tank ST from whereit is pumped to the pressure tank PT as set forth in said Patent1,784,310.

Between the train lines PL and each storage tank PS is a check valve CVwhich prevents the local storage tank from discharging back into theline in theevent of a break in the train line. But each tank PS deliversto the proper valve BV by way of line 2.

The brake valves BV are arranged so that a continuous current isrequired to hold the valves in release positions. As this current isdiminished, the brakes are applied, reaching full application when thecurrent approaches zero. Full application consequently also occurs whenthe electric train control line is broken for any reason.

The electric train control line is also subject to accidentalshort-circuits which might act to set the brakes on only part of thetrain. Therefore, for protection against any change in the resistance ofthe line due to open circuit or short circuit, partial or complete,there is used the Wheatstone bridge arrangement of resistances AL, RA,RW and the electromagnetic valves BV, with a relay G connected acrossthe bridge between resistances AL and RA on one hand, and RW and BV onthe other hand. AL and RA are relatively high resistances; and AL ispreferably arranged with suflicient self-inductance so that its timeconstant is substantially the same as the control line containing theelectromagnetic valves. This keeps the bridge in balance duringmomentary changes in current flow.

The relay G which is connected across the bridge, as shown, is balancedin open position during normal operation, but any .substantial change inthe resistance of the line, greater or less than normal, will close thecontact on said relay G and close the operating coil of a circuitbreakerCB to open the train line control circuit. This acts through theelectromagnetic valves BV to set the brakes on all cars at once.

As more or fewer cars are used in the line the resistance RW is adjustedso that the relay G is in balance and this balance is maintainedregardless of the current used to operate the valves. Control of thesystem is entirely through the rheostatic controller BP which carriesthe current in the line to the valves BV. This. variation may also beobtained by taking variable taps from the battery instead of using arheostat.

Application of the brake system of Fig. 2 is accomplished by moving therheostatic controller BP so as to cut out resistance. This increases thecurrent in the coils E and forces down the levers 35 to connect lines PLwith the brake lines BR so that pressure flows against the bellows l.Under this condition the springs I! are stretched. Under this conditionalso a balancing pressure is applied at diaphragms DA which have amechanical connection with the levers 35 to counter-balance thebrake-applying effect of coils E for aiding the return action of springsll. Thus, the three-way valves 15 are self-balancing or selflapping,that is to say, they take up positions which are proportional to theposition of the rheostatic controller BP.

Release is accomplished by returning the rheostatic controller BP toinsert resistance, whereupon the action is reversed. In this case,weakening of current in the coils. E permits the sum of the pressures ondiaphragms DA and springs E7 to return the valves IE to a closedposition and then to a'position wherein the brake cylinders BR aredrained through the three-way valves l5 to the release lines RL.

It will be noted in connection with Fig. 2 that the solenoids of thebrake-valves BV are connected in series.

As shown in Fig. 3, instead of an electric line transmitting the controlpressure from the controller in the head car it is possible to usehydraulie or pneumatic means operating through a separate pipe line.Pistons or expansion bellows supplant the electromagnets previouslydescribed. A reduction of pressure may be used to apply the brakes.

The controller comprises any suitable three-Way valve, such as valveBVH, adapted to admit variable pressure to the control line CL andexhaust to the sump. This valve is self-lapping or selfbalancing byreason of back-pressure from diaphragm DA acting against spring S. Thespring S is located to transmit force from the manually operable lever Lto the lever B of the valve BVH. The valve BVH is hand or foot actuatedso that a variable pressure and/or movement on the control lever thereofwill effect corresponding pressure variation in the control line CL.

Upon manually controlling the valve BVH, hydraulic pressure exerted inthe control line CL acts to move bellows CB against the differentialaction of a spring Hi. Control is balanced by the pressure under adiaphragm DA under valve BVH. By means of a three-way relay valve 45pressure is shut off from the pressure supply line PL to the brake lineBR and later to connect the brake line BR to the exhaust or release lineRL. This effects setting of the brakes if they are spring set. Uponrelease, the inverse series of events occurs.

If "the brakes are to be directly applied, it is only necessary tochange the relative actions of the valves BVH and 3 I.

For instance, if the lines PL and RL connected to valve ll areinterchanged (leaving the other apparatus as shown) then, in the case ofdirectly set brakes, increased pressure in the control line will act toapply pressure to the brake cylinder and apply the brakes.

It will be seenthat in the modification of Fig. 3 the bellows CB, withdiaphragm DA, valve ll and associated parts, takes the place of theelectrical valve EV of the forms shown in Fig. 2 and the handle L ofvalve BVH takes the place of the rheostat BP.

It will be seen from the above that the valve BVH in Fig. 3 and valve BPin Fig. 5 may each be considered as a master control valve, the actionof which is relayed to the valve M (Fig. 3) or the valve 95 (Fig. 5).The relay action in Figs. 2 and 4 is from the rheostat BP to the brakevalves. It will therefore be clear that one master valve such as BVH orBP, as the case may be, can serve a plurality of valves 4| or l5, as thecase may be, in different cars.

In certain classes of trains it is desirable to open and close doors inconjunction with the stopping and starting of the train. At the sametime it is desirable to interlock the door operation so that the brakescannot be released while the doors are open.

The doors may be operated by fluid means from the same power sources asthe brake cylinders but through a separate door control line. If thebrake control circuit is electrical, the same may be opened by asuitable series contact at each door so that the brake control circuitis opened whenever any door is not completely closed. This makes itnecessary for all the doors to be closed before the train can bestarted.

Fig. 4 illustrates the system last referred to. The doors D are adaptedwhen open to cause opening of the contacts 2 I, this being done by theaction of springs 23. Thus when the doors are open, the control circuitis open and hence the brakes are set in the manner hereinbefore described.

It is clear that, where a fluid control line is used, the fluid circuitmay be opened and closed by means of a suitable valve operable at eachdoor, each valve comprising a substitute for the contact 2i. Anembodiment of this feature is shown in Fig. 5 wherein the doc-rs D arecaused to open the pressure line PL at valves DS whenever the doors areall fully closed. If the valve BP is set for release, the brakes willtake release position when, and only when, the last door closes, becausethat, is the only way in which pressure can reach the cylinder BR inorder to coinpress spring 5 to take pressure from the brake shoes.

It should be understood that the valve BVI-I in Fig. 3 and the doorvalves DS in Fig. 5 and the door switches 2| in Fig. 4 all constitutesecondary means for controlling the main three-way device (4! in Fig. 3;H5 in Fig. 5; and I5 in Fig. l, when read in connection with Fig. 2).

In view of the above, it will be seen that the several objects of theinvention are achieved and oth r advantageous results attained.

As many changes could be made in carrying out the above constructionswithout departing from the scope of the invention, it is intended thatall matter contained in the above description or shown in theaccompanying drawings shall be interpreted as illustrative and not in alimiting sense.

I claim:

1. Control apparatus comprising brake lines, release lines, pressurelines, and control lines, a three-way valve associated with saidpressure lines, brake line and release lines, means for operating saidvalve by pressure in said control lines comprising a movable diaphragm,a second diaphragm operable in connection with valve moving means, saidsecond diaphragm being subject to pressure in said brake lines, wherebyfluid control is used for operating said valve and whereby balancedconditions are the same for each position of said valve.

2. Brake control apparatus comprising a pressure tank, a sump tank, apressure line from the pressure tank, a release line to the sump tank, abrake line, a self-lapping three-way valve between the pressure andbrake and release lines, fluid-operated means for operating saidthreeway valve, and a fluid control line connecting the pressure tankwith said fluid-operated means.

3. Brake control apparatus comprising a pressure tank, a sump tank, apressure line from the pressure tank, a release line to the sump tank, abrake line, a self-lapping three-Way valve between the pressure andbrake and release lines, fluid-operated means for operating saidthreeway valve, a fluid control line connecting the pressure tank withsaid fluid-operated means, and a manually operated three-way valvebetween the pressure line, release line and control line.

4. Brake control apparatus comprising a pre sure tank, a sump tank, apressure line from the pressure tank, a release line to the sump tank, abrake line, a self-lapping three-way valve between the pressure andbrake and release lines, fluid-operated means for operating saidthreeway valve, a fluid control line connecting the pressure tank withsaid fluid-operated means, and a manually operated three-way valvebetween the pressure line, release line and control line, saidlast-named valve being of the self-lapping type.

5. Brake control apparatus comprising a pressure tank, a sump tank, apressure line from the pressure tank, a release line to the sump tank, abrake line, a three-way valve device between the pressure and brake andrelease lines, hydraulic means for operating said three-way valve devicecomprising a three-Way valve, 2. control line from said last-namedthree-way valve to the three-way valve device, and pressure and releaselines associated with said last-named three-way valve.

6. Brake control apparatus comprising a pressure tank, a sump tank, twoconnections from the pressure tank to the sump tank, a brake lineassociated with one connection, a control line associated with the otherconnection, a brake valve associated with the brake-line connection anda control valve associated with the control-line connection,fluid-operated means for operating the brake valve, said control valvebeing adapted to vary the pressure in the control line to effectoperation of said brake valve.

7. Brake control apparatus comprising a pressure tank, a sump tank, twoconnections from the pressure tank to the sump tank, a brake lineassociated with one connection, a control line associated with the otherconnection, a brake valve associated with the brake-line connection anda manually operated control valve associated with the control-lineconnection, fluid-operated means for operating the brake valve, saidmanually controlled valve being adapted to vary the pressure at thecontrol line to efiect operation of said brake valve, said manuallyoperated valve being selflapping.

8. Brake control apparatus comprising a pressure tank, a sump tank, twoconnections from the pressure tank to the sump tank, a brake lineassociated with one connection, a control line associated with the otherconnection, a self-lapping brake valve associated with the brake-lineconnection and a self-lapping manually operated control valve associatedwith the control-line connection, fluid-operated means for operating thebrake valve, said control valve being adapted to vary the pressure atthe control line to effect operation of said brake valve.

HARVEY S. PARDEE.

